Richardson made her film debut at age four, playing one of her mother's bridesmaids in Charge of the
Light Brigade (1968), directed by her father. Trained at the Central School for Speech and
Drama, Richardson did her first professional stage work at the Leeds Playhouse in 1983 then went on to
specialize in Shakespeare at the Old Vic.

Richardson's television career began in 1984 when she appeared in the mini-series Ellis Island playing
the part of a young whore. She then went on to appear in The Adventures of Sherlock Holmes II in
1985, followed by Ghosts in 1986.

In the company of her mother Vanessa and her Aunt Lynn, Richardson made an excellent impression in a
1985 staging of Chekhov's The Three Sisters; the following year, she won the London Theatre Critics
Award for Most Promising Newcomer.

Her film roles ranged from passive to aggressive but have always been distinctive. Among Richardson's
most memorable film assignments were A Month in the Country (1987), The Handmaid's Tale (1990), Widows Peak (1994), and the successful 1998 remake of The Parent Trap.

In 1994, Richardson married actor Liam Neeson and the two appeared together in the film Nell. Neeson and Richardson also appeared together on stage on Broadway in Anna Christie.

Richardson then went on to appear in the West End in High Society, and as Sally Bowles in Cabaret on Broadway for which she won a Tony Award. Other film projects include Never Better and Wakin' Up in Reno (both 2000), Maid in Manhattan (2002) and The White Countess (2006), in which she again starred with her mother.

On March 16, 2009, Richardson suffered a serious head trauma after falling during a skiing lesson on a beginner slope in Quebec. Her ski instructor called paramedics to the scene, but Richardson seemed fine, was joking and refused medical help, returning instead to her hotel room. The instructor insisted on staying with her and when the actress complained of a headache, immediately called an ambulance. Richardson was taken to a nearby hospital, then transfered to another one in Montreal on the same day. Her husband, who was shooting a film in Toronto at the time, immediately flew to be by her side, and she was transfered to Lenox Hill Hospital in New York City the following day. Richardson was taken off life support on March 18, 2009, two days after her fall. She died shortly afterwards.

Richardson and Neeson have two sons, Micheal, born in 1995, and Daniel Jack, born in 1996.